import numpy as np
# a=np.array([[1,2,3],[4,5,6],[7,8,9],[10,11,12]])
# print(a)
# print(a.ndim)
# print(a.shape)
# print(a.size)
# print(a.dtype)
a=np.array([[1,2,3,4],[5,6,7,8],[9,10,11,12]])
# print(a[0])
# print(a[1:5])
# print(a[:8:2])
# print(a[::3])
# print(a)
# print(a[0,2])
# print(a[0:2,1:3])
# print(a[2,::2])
# print(a[::2,:2])
print(a[1,2])
print(a[1:3,1:3])
print(a[1,::2])
print(a[::2,:3])

